I started collecting pop music in the second half of the 1950's. My collection of 45 rpm discs covers 1955 - 1975 approx and my CD collection extends this interest back to 1950 (extend back!). Whilst I've updated virtually all my pop music tracks either by purchasing CDs or creating them, I've kept all the 45s. It's only since the mid 70's that I started my collection of theatre related discs and soundtracks.
It helps that I've only ever lived in three homes in my life. We've been in this one for 26 years. and the home is certainly large enough (ask Jose) to store the collection.
The DVDs just seem to accumulate. I rarely buy any when they are first issued so it's not really an expense of great magnitude.